(Solved): A secondary wastewater treatment process consists of a complete-mix circular biological reactor an ...

A secondary wastewater treatment process consists of a complete-mix circular biological reactor and associated secondary clarifier. This process has an influent flow of \( 2.5 \mathrm{ML} / \) day and maintains a mixed liquor volatile suspended solids concentration of \( 2850 \mathrm{mg} / \mathrm{L} \). The secondary clarifier produces an effluent stream of \( 2.0 \mathrm{ML} / \) day with negligible suspended solids (assume \( 0 \mathrm{mg} / \mathrm{L} \) ) and a sludge of VSS \( 6580 \mathrm{mg} / \mathrm{L} \). Following effective primary treatment, influent to the activated sludge process has negligible concentration of suspended solids (assume \( 0 \mathrm{mg} / \mathrm{L} \) ) and a BOD of \( 600 \mathrm{mg} / \mathrm{L} \). This system is operated to maintain constant volume in the process tanks and constant MLSS concentration. (a) Produce a schematic illustration of this secondary wastewater treatment process, including (5 marks): a. important process components, b. hydraulic flows in, out and within the system, c. numerical values for all flow rates, concentrations, or other data provided in the question. (b) Determine the RAS flow rate ( 8 marks) (c) Determine the WAS flow rate (2 marks)